Yellow diffusion-fast color formers of the benzimidazole class



Patented Mar. 14, 1950 UNITED STATES PATENT O F'FICE General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No'Drawilig. Application November 9, 1948, Serial No. 59,203

Claims.

The present invention relates 1 to non-diffusing colorforming components of the Z-phenyl benzimidazole class, having improved solubility characteristics and capable of yielding upon colorforming development yellow dyestuff images-of enhancedspectral characteristicsand exceedingly fine grain.

-In the present day practical application of color photography, the'methodmost generally used'involves the employment of 'a monopack having differently sensitized superimposed silver halide emulsion layers, each containing adyestuff component fast to 'diiiusion in the emulsion and which upon development of the exposed monopack with a primary aromatic amino developer yields subtractively colored dyestufi images, i. e., cyan,-magenta and yellow.

The yellow component generally employed is an openchain keto-methylene compound such as acetoacetanilide, benzoyl-acetoacetanilide, and the like. For most purposes the dye images produced by such components are satisfactory although they leave something to be desired so far as spectral characteristics and grain are concerned. Another disadvantage in the utilization of such components is their low solubility, and particularly'their loW solution stability.

I have now found that the disadvantages which manifest themselves in the utilization of'th'e generally employed yellow color formers can be overcome with the production of dyestuff images of enhanced spectral characteristics a'nd'fine grain by employing for the formation of the yellow image in the color forming development method a 2-;phenyl benzimidazole containing a water solub'i-lizing group in the fused-on benzene ring, a radical imparting fastness to diffusion on the nitrogen atom in the 1-position of the heterocyolic ring, and an acetamido radical in the phenyl ring attached to the carbon atom in 2- position. These color formers yield very desirable azomethine dye images by color forming development with developers of the p-phenylenediamine type, and in addition have very improved solubility characteristics when compared to the keto methylene compounds generally employed in the color development process.

Photographic emulsions containing yellow color formers of the aforestated type and the processing of such emulsions by color forming development with the formation of improved yellow dye images constitute the purposes and objects of the present invention.

Thecolor formers contemplated herein maybe depicte'd'by the following structural formula:

wherein R is a phenyl radical, a carbon'atom of which is directly linked to the carbon atom of the heterocyclic ring, 1. e-.-,-phenyl;*halogen phenyl, i. e., chlorophenyl, bromophenyl -and the like; alkyl phenyl, i. 6,, toluyl, ethylphenyl and the like; 'alkoxyphenyl, ii-e, 'methoxypnenyl',"emeryphenyl and the like, is the'radi'c'al 'NH.CZCH2.A,

R2 is an alkyl chain containing at least 10 carbon atoms, i. e., decyl, undecyl, do'decyl, myristyl, tetradecyl, pentadecyl, octadecyl and thelike; R3 is a Water solubilizing'group such as sulfo, carboxy'and the'like'A is an alkyloyl radical, i. e., acetyl, propionyl, butyryL'ahd the like,"aroyl{i."e., benzoyl, naphthoyl, and the like, cyano or carbethoxy; and his 1 or 2.

Examples of compounds embraced byth'e above formula are the following: V

(l) 2-(4-benzoylacetaminophenyl) 1 octadecylbenzimidazole-5-su1fonic acid.

(llisHs'l -(2) 2-(4' b nzeyiacetamino henyo Hanan-"- benz'imida'z'oIe 5-sulfoni-c acid. (3) 2-(4 -benzoy1acetaminopheny1) 1 istylbenzimidazole=5 sulfonic acid.

l) 2 (3'=benzoylatafninbphenyl) l -'octadecylbenzimidazole-ti sulfonic acid.

ilic HOaS . U r (6) 2-[(3-benzoylacetamino-4'-chloro) phenyll-1-octadecylbenzimidazole-5-su1fonic acid.

7) 2-[(3'-benzoylacetamino 4' methoxy)- phenyll-l-octadecylbenzimidazole 5 sulfonic acid.

CxaHu cooH, N/ 7, flurooomco-O (8) 2-[(3'-benzoylacetamino 4' methoxy) phenyll -1-decylbenzimidazole-5-sulfonic acid.

(9) 2- (4' -acetoacetaminophenyl) -1-octade'cylbenzimidazole-S-sulfonic acid.

\OONZELC 0.01120 0.0mm HOaS- N y (12) 2-(4'-cyanoacetaminophenyl) 1 octadecylbenzimidazole--sulfonic acid.

HOaS

HOaS- The color formers are prepared by heating a 2-(4'-aminophenyl) -1'-long chain alkyl benzimida-zole-5-sulfonic or carboxylic acid with an acyl acetic ester while mixing or by heating the aforesaid components in the presence of pyridine to a temperature of about 100-430 C.

The parent benzimidazole, on the other hand, is

prepared by heating a 3-amino-4-long alkyl chain aminobenzene sulfonic or carboxylic acid with the desired nitro benzene carboxylic acid chloride in the presence of pyridine or any other suitable acid binding agent, the nitro compound then being reduced to the corresponding amine. Preparation of the intermediate is analogous to the method described in my copending applicationSer. No. 745,113, filed April 30, 1947, with the exception that the l-hydroxy-Z-naphthoyl chloride is replaced by the desired nitro benzoyl chloride, the resulting product then being reduced to the corresponding amine.

Emulsions designed for yielding the desired yellow image are prepared by dispersing a small quantity of the color former, i. e., about .5 gram of the color former in 100 cc. of a photographic silver halide emulsion, coating the emulsion on a support and drying the same. The film containing the emulsion may be processed by the negative-positive method or by the reversal method while utilizing for color development a primary aromatic amino developer such as p-diethylamino-aniline and the like.

The invention is further illustrated by the following examples, but it is to be understood that the invention is not restricted thereto.

Example 1 mHm parts of 2-(4'-aminophenyl)-1-octadecylbenzimidazole-5-sulfonic acid and 15 parts of benzoylacetic ester are mixed in a Werner- Pfleiderer and heated for 4 hours at lbs. steam pressure.

The crude product is purified by taking up in 125 parts of methanol and heating at reflux C.) for 1 hour. After cooling to 30-35 0., the product is collected on a filter, washed with 50 parts of methanol, sucked dry, then air dried.

.5 gram of the purified product is dispersed in 100 cc. of a photographic silver bromide emulsion.

The emulsion is coated on a transparent support and dried. After exposure the film is developed in a color forming developer comprising an aqueous solution of 10 parts of sodium sulfite, 15 parts of p-diethylamino aniline, 2.5 parts of sodium carbonate, and '70 parts of potassium bromide. The silver and dye image is thus formed. After removal of the silver by bleaching in potassium ferrocyanide solution and subsequent fixing, a bright yellow dyestufi? image of very fine grain is obtained.

Example 2 30 parts of 2-(4-aminophenyl)-1-octadecylbenzimidazole-5-sulfonic acid, 15 parts of benzoylacetic ester, and 200 parts of pyridine are heated at 1l0-120 C. for 4 hours. The reaction mixture is diluted with 100 parts of water, and then drowned in a mixture of 00 parts of concentrated hydrochloric acid, and 1000 parts of ice-water. The crude product is collected on a. filter, Washed twice with cold water, sucked dry as possible, and air dried.

The crude product is purified by taking up in 200 parts of methanol and heating at reflux (65 C.) for hour. After cooling to 20-25 C., the product is collected on a filter, washed with parts of methanol, sucked dry, then air dried. The product is the same as that of Example 1 and may be used as there indicated.

Example 3 0 181331 1 o Nnooomoo-c HOaS- N/ This product is prepared in the same manner as Example 1 from 30 parts of 2-(3-aminophenyl) 1 octadecylbenzimidazole 5 sulfonic acid, and 15 parts of benzoylacetic ester.

An intense yellow dye image of very fine grain is obtained by dispersing the color former in a asoaasv photographic silver bromide emulsion and processingthe emulsion as in Example 1.

Example 4 181131 This product is prepared in the manner of Example 1 from 28 parts of 2-(3',5-diaminophenyl) 1 octadecylbenzimidazole 5 sulfonic acid, and 25 parts of 'benzoylacetic ester.

Dye images similar to those obtained in Examples 1 and 3 result when utilizing the above color former for the production of an azomethine dye image.

NH.CO.CH2.CO.-

Example 5 C l8 37 C- Cl HO S- a NH.OO.OH.CO.

This product is prepared in the same manner as Example 1 from 30 parts or" 2-[(3-amino-4'- chloro) phenyl]-l-octadecylbenzimidazole-5-sulionic acid, and 15 parts of benzoylacetic ester.

A bright yellow azomethine dye image is produced by utilizing the above color former as in Example 1. Such dye images are characterized particularly by the fineness of their grain.

Example 6 I mHa'I This product is prepared in the manner of Example 1 from 32 parts of 2-[(3-amino-4-methoxy) phenyl] 1 octadecylbenzimidazole-5-sulfonic acid, and 18 parts of benzoylacetic ester.

A bright yellow azomethine dye image is produced by utilizing the above color former as in Example 1. Such dye images are characterized particularly by the fineness of their grain;

Example 7 1 12 31 This product is prepared in a manner similar to Example 1 from 27 parts of 2-(4'-aminophenyl) 1-octadecylbenzimidazole 5 sulfonic acid, and 15 parts of acetoacetic ester.

A bright yellow azomethine dye image is produced by utilizing the above color former as in Example 1. Such dye images are characterized particularly by the fineness of their grain.

Example 8 C NH.OO.CH,.CO.OC.H.

This product is prejgiared a manner similar to Example 1 from 27 parts of 2'-(4'-amii'1'ophenyl) --1 octadecylbenzimidazole 5 sul'foni'c acid, and 12 parts of diethyl malon'a'te.

A bright yellow azomethinedye image is produced by utilizing the above color former as in 37 parts of 2-(4'-aminophenyl)-1-octadecylbenzimidazole-5-sulfonic acid and 50 parts of cyanoacetic ester are heated at 145-150" C. for 4 hours. To the cooled reaction mixture there is added parts of methanol, and 75 parts of ethyl acetate. The product is collected on a filter, washed with '75 parts of ethyl acetate, sucked dry, and then air dried.

A bright yellow azomethine dye image is produced by utilizing the above color former as in Example 1. Such dye images are characterized particularly by the fineness of their grain.

Various modifications of the invention will occur to persons skilled in this art, and I therefore do not intend to be limited in the patent granted except as necessitated by the appended claims.

I claim:

1. A photographic silver halide emulsion containing as a yellow color former fast to diffusion a compound of the following formula:

wherein R- is a phenyl radical, R1 is the grouping -NC.CO.CH2.A, R2 is an alkyl radical containing at least 10 carbon atoms, R3 is a Water solubilizing group, n is selected from the class consisting of 1 and 2, and A is a member of the class consisting of alkyloyl, aroyl, cyano and carbethoxy.

2. A photographic silver halide emulsion containing as a yellow color former fast to diffusion the compoundv 2-(4-benzoylacetamino phenyl) l-octadecyl benzimidazole-Ea-sulfonic acid.

3. A photographic silver halide emulsion containing as a yellow color former fast to diffusion the product 2-(3'-benzoylacetamino phenyD-lcctadecyl benzimidazole-S-sulfonic acid.

l. A photographic silver halide emulsion containing as a yellow color former fast to diifusion the product 2- (3.5'-di-benzoylacetamino) phenyll-l-octadecyl benzimidazole-5-sulfonic acid.

5. The process of producing yellow dyestuff images in a photographic silver halide emulsion which comprises exposing an emulsion containing as the color former a compound of the following formula:

Ra l wherein R is a phenyl radical, R1 is the grouping NH.CO.CH2.A, R2 is an alkyl radical containing at least 10 carbon atoms, R3 is a water solubilizing group, n is selected from the class consisting of 1 and 2, and A is a member of the class consisting of alkyloyl, aroyl, cyano and carbethoxy, and developing the exposed emulsion with a. color forming developer comprising a, primary aromatic amino developer.

WINFRED C. CRAIG.

8 REFERENCE oi'rlifi The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Namev Date 2,179,239 Wilmanns et a1 Nov. 7, 1939 2,186,849 Wilmanns et a1 Jan. 9, 1940 m 2,373,821 Frohlich et a1. Apr. 17, 1945 Certificate of Correction Patent No. 2,500,487

March 14, 1950 WINFRED C. CRAIG It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 46, for that portion of the formula reading NC.CO. read NH.OO.;

, and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 4th day of July, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents. 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING AS A YELLOW COLOR FORMER FAST TO DIFFUSION A COMPOUND OF THE FOLLOWING FORMULA: 